Resolves the confusing error message `ripgrep exited with code null that occurs when a search operation is cancelled or aborted (#14267)

Co-authored-by: Gal Zahavi <38544478+galz10@users.noreply.github.com>

packages/core/src/tools/ripGrep.test.ts

@@ -1009,10 +1009,10 @@ describe('RipGrepTool', () => {
 
       const result = await invocation.execute(controller.signal);
       expect(result.llmContent).toContain(
-        'Error during grep search operation: ripgrep exited with code null',
+        'Error during grep search operation: ripgrep was terminated by signal:',
       );
       expect(result.returnDisplay).toContain(
-        'Error: ripgrep exited with code null',
+        'Error: ripgrep was terminated by signal:',
       );
     });
   });